#VU19568 Use-after-free in Linux kernel - CVE-2018-20856

Vulnerability identifier: #VU19568

Vulnerability risk: Low

CVSSv4.0: 1.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-20856

CWE-ID: CWE-416

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

The vulnerability allows a local attacker to execute arbitrary code on a targeted system.

The vulnerability exists due to a use-after-free error when the "__blk_drain_queue()" function in the "block/blk-core.c" file mishandles error cases. A local authenticated attacker can access the system and execute an application that submits malicious input, cause a use-after-free memory operation error and execute arbitrary code on the targeted system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: 4.18.1 - 4.18.6

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External links
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.7
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=54648cf1ec2d7f4b6a71767799c45676a138ca24
https://github.com/torvalds/linux/commit/54648cf1ec2d7f4b6a71767799c45676a138ca24

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.